(1) Field of the Invention
This invention relates to vibration dampeners, and is directed particularly to a molded dampener of gel material, the dampener having no fluid component and requiring no housing.
(2) Description of the Prior Art
Electrorheological (ER) fluids are adapted to transform from a fluid to a semi-solid, or pasty substance, capable of resisting an applied stress, when the fluid is activated by an electric potential. When the electric potential is removed, the semi-solid substance reverts to the original fluid. ER fluids are two-phase systems containing micron sized particles suspended in a carrier fluid. When the ER fluid is subjected to an electric field, the particles polarize and develop a network of three dimensional chains. The ER fluid develops an electric field dependent yield stress, when activated by an electric field. In the activated state, the ER fluid turns semi-solid, and resists an applied shear stress, providing the applied load does not exceed the developed yield stress. The activation time from the fluid state to the semi-solid stress resistant state is typically on the order of milliseconds. The many applications of such fluids includes use in clutches, viscous dampers, valves and active engine mounts.
There have been developed systems for the dissipation of vibrational energy through the interaction between a plunger mechanism and the ER fluid. The ER fluid properties are actively altered by the magnitude of an electric field applied; thus, the response of the structure readily may be altered and controlled.
Devices designed to employ ER fluids suffer from the requirement of a fluid and a container for housing the fluid in a leak-proof manner. Further, in all fluids employed, the particles tend to settle to the bottom of the housing. Once the particles have settled to the bottom of the fluid, in order to be effective, the mixture must be remixed before further use. Still further, the requirement of a housing dictates a set configuration and size of dampener, not amenable to change.
Accordingly, there is a need for a vibration dampener which does not employ a fluid, and therefore has no particle settlement problem, and no requirement for a leak-proof container, or any container. A further need exists for a dampener which easily can be configured and sized to a particular application.